Electromagnetic switching device or relay.



s. H. EVERETT.

ELECTROMAGNETIC SWITCHING DEVICE 0R RELAY.

APPLICATION FILED AUG.20. \912.

1,278,448. Patented Sept. 10,1918.

hue/War: Samam/ h. five/e17 UNITED STATES PATENT OFFICE.

SAMUEL HARRISON EVERETT, OF BROOKLYN, NEW YORK, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

Specification of Letters Patent.

ELECTROMAGNETIC SWITCHING DEVICE OR RELAY.

Patented Sept. 10, 1918.

Original application fil ed March 11, 1915, Serial No. 13,696. Divided and this application filed August 20,

i 1917. Serial No. 187,281.

' To all whom it may concern Be it known that I, SAMUEL H, EVERETT, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Electromagnetic Switching Devices or Relays, of which the following is a full, clear, concise, and exact description.

This invention relates to electromagnetic devices or relays and more particularly to such devices which are subjected to alternating currents of Widely different-frequencies, to direct current alone, or to direct current upon which is superimposed alternating currents of widely different frequencles. This application is a division of my copending applicatiomSerial No.1 3,696, filed March 11, 1915, and assigned to the same assignee as the present application.

The object of this invention is to provide,

a relay which will operate on direct current alone or on direct current upon which is superimposed alternating currents of widely different frequencies but {which will not operate upon any of those alternating currentsalone of values experienced in service.

This result is accomplished by providing a relay having a core upon which there is an energizing winding positioned intermediate the ends of the core, with supplementary closed circuited coils or non-magnetic hollow cylindrical members surrounding the core and located upon each side of the energizing winding. Preferably these closed'circuited coils consist of large masses of copper. These coils are so proportioned and the energizing winding so positioned that the leakage and demagnetization effects due to them will be such as to permit of the operation of the relay on directcurrent alone or on direct current upon which is superimposed alternating currents of any frequency, but will not allow of its operation, upon alternating currents alone.

The invention will be more clearly underf stood by reference to the accompanying drawing wherein:

Fi re 1 is a side elevation of a relay showing one embodiment of this invention; Fig. 2 is a side elevation, partly in section, of the relay of Fig. 1; Fig. 3 is a similar section showing a modification of the shortcircuited windings, and Fig. 4 shows a multi-frequency telephone signaling circuit employing the relay of this invention.

As shown in Figs. 1 and 2 the relay may consist of a core 5, about which is placed an energizing winding 6 positioned intermediate the ends of the core 5.. There is also mounted upon the core 5 short circuited coils 7 and 8, one on each side of the energizing winding 6. These short circuited coils 7 and 8 consist preferably of non-magnetic hollow cylindrical masses of copper. The energizing winding 6 and core 5 and the closed circuited c'oils 7 and 8 may be suitably eparated by means of insulating material 9. At one'end of the core is provided a collar 10 separated from the closed circuited coil 7 by an insulating washer 11. On the washer 11 there may be located terminals 15 and 16 suitably mounted, to which are attached leads from the energizing winding 6. The core 5, together with the above described parts mounted thereon, may be inclosed in a shell 17 of magnetic material, openings being provided in the closed end 18 thereof, with which register the terminals 15 and 16 and the end of the core 5. The core 5 is firmly secured to the closed end 18 of the shell 17 by means of a nut 19 having screw-threaded engagement with the end of the core. The terminal 20 to which one lead of a control circuit may be attached, is suitably secured to the core 5. Near the open end of the shell 17 there is mounted upon the shell a yoke 21 of nonmagnetic material to which is pivoted an armature 22 in operative relation to the free end of the core 5. A spiral spring 25 secured at one end to a. finger 26 mounted on a shell 17 and at the other end to a finger 27 attached to the armature 2 2, normally holds the armature 22 away from the end of the core 5 as in Fig. 1. A contact spring 28 mounted on the armature 22 is electrically connected to the terminal 20 through the relay structure. The terminal member 29, to which is attached the other lead of forward end of terminal member 29, which is bent as shown in Fig. 1 may be mounted an adjustable contact stud 30. Normally the action of spring 25 maintains contact spring 28 and contact stud 30 in engage ment.

In the. modification of Fig. 3 the shortcir'cuited windings 7 and 8 are replaced by a number of non-magnetic metallic washers positioned on either side of the energizing winding 6; otherwise the relay structure is the same as that of Fig. 2 and identical parts are designated by identical reference characters. J

The dimensions of the important elements of an actual relay made up in accordance with this invention are as follows:

Length of core 5 from collar 10 to The'energizing winding consists of 3300 turns of No. 35 insulated copper wire.

One important use for the relay of this invention is shown in the multi-frequency telephone signaling circuit of Fig. 4 wherein it is designated by the reference character 42. The function of this relay in that circuit is to automatically cause the disconnection of the ringing current from the subscribers line upon the response of any subscriber by the removal of his receiver from its hook. In order to accomplish this re-. sult the relay must not operate on alternating current supplied by the multi-frequency sources of current 51, 52, 53 and 54; but it must operate upon direct current alone supplied by battery 48 or upon direct current upon which is superimposed alternating current of any of the frequencies supplied by said sources of ringing current. The operation of the system of Fig. 4 is briefly as follows:

Upon insertion of the calling plug into the jack 35 of the wanted subscribers line, a circuit is completed from battery 36, through the winding of relay 37, sleeve contacts of the calling plug and jack 35 and the windings of the usual cutoff relay 38 to ground, operating relay 38, thereby removing the usual line relay 39 from the limbs of the subscribers telephone line. Current in the above path also actuates relay 37, which completes a circuit from battery 36, through contact 40 of relay 37, contact 41 of relay 42, contact 43 of relay 44, and winding of relay 45 to ground, actuating relay 45, which opens the tip and ring strands of the cord circuit and connects the tip side to ground at contact 46 and the ring side through the winding of tripping relay 42 at contact 47.

By means of the multi-party key 49 any one of the sources of alternating current 51,

erator operates a button of the locking ring- 7 ing key 49 connecting to one of the middle contacts of this key alternating current of the frequency to which the bell at the wanted substation is turned. Suppose that the left-hand contact of key 49 has been closed, a circuit is then completed from grounded batery 48,- through the interrupter 50, generator 51, or through the interrupter .56, depending upon the relative positions of the interrupters 50-and 56, left-hand alternate contact of. the ringing key 49, winding of the. tripping relay 42, alternate closed contact 47 of relay 45, ring side of the line, bells 60, 62, 64 and 66, and condensers 61,

'63, 65 and 67 in parallel, tip side of the line and alternate contact 46 of relay 45 to ground. Only one of the bells, say 60, responds to this current, since it alone is' tuned to respond to the frequency of source 51. The condenser 61 at the subscribers station prevents the passage of 'direct current. Tripping relay 42, therefore, does not operate when in serles with the bells 60, 62, 64and 66 and the condensers 61, 63, 65

- and 67.

When, however, the receiver at one of the subscribers stations is removed from the switchhook, a low resistance path in shunt with the bells and condensers is closed,

whereupon tripping relay 42 operates, opening the short'circuit of relay 44. Relay 44 thereupon operates and locks up, shortcircuiting relay 45, which releases to dis nating current of any of the different frequencies is connected thereto causes the tripping relay 42 to operate. It is, therefore,- clear that to function properly the relay 42 must not operate when the receiver is on the hook and alternating current of any of the different frequencies is alone connected to the line, but must operate when the recelver is off and either direct current alone or direct current upon which is superimposed any of the various frequencies is connected thereto.

Relays have been produced heretofore to operate when traversed by direct current alone or by direct current upon whichis superimposed alternating current of a single frequency, and not to operate when traversed alone by alternating current of that particular frequency; but no relay has heretofore been produced, which would operate, as hereinbefore described, when alternating current of any of a plurality ofv widely different frequencies was being used. 10.

Such a relay is of very great importance and utility in multi-frequency ringing circuits of telephone signaling systems,v such as herein described; In heretofore known systems, it has been necessary to use a separate tripping relay in a cord or telephone circuit for each frequency of alternating current, while now it is possible by the utilization of the tripping relay embodying the present invention to employ only one trip ping relay in a cord or trunk circuit to accomplish the same result.

What is claimed is:

1. In arelay comprisinga core and an armature mounted adjacent to one end of said'cor e, an energizing winding at an intermediate position on said core and apair of short-circuited windings for said core, one

' at eachside of said energizing winding.

2. In a relay comprising a core and an armature mounted adjacent to one end of said core, an energizing winding at an intermediate position on said core, and a pair of nonmagnetic conducting hollowcylindrical members completely surrounding said core, one at each side of said energizing winding.

3. In a relay comprising a core, and an armature mounted adjacent to one end of said core, an energizing winding atan intermediate position on said core and a lurality of non-magnetic conducting was ers surroundingsaid core-on both sides of said energizing winding.

4.. In a relay, a tubular magnetic member open at one end, a magnetic core within said membenan energizing winding at an intermedlate pos tion on sand core, a hollow cylindrical non-magnetic conducting memher surrounding said core adjacent to one mediate position on said core, a short-circuited winding for said core at one side'of said energizing winding, a second short-circuited winding for sald core at the other side of said energizing winding and an armature adjacent to said core at the open end of said tubular member.

6. Ina relay, a tubular magnetic member open at one end, a magnetic core within said member, an energizing winding at an intermediate position on said core, a plurality -of non-magnetic conducting washers surrounding said core located on both sides of said energizing winding, and an armature adjacent .to said core at the open end of said tubular member.

7. In a relay for use in a circuit comprising sources of direct current and of multifrequency alternating current, a core, an

energizing winding thereon, an armature in operating relation to said core and demagnetizing meansenergizable by alternating currents of any of the diflerent frequencies from the multi frequency source to prevent the core from attracting its armature under the influence of said currents, said means being non-responsive to the direct current, and said energizing winding being adjusted to enable the direct current to energize said core sufiicientl to attract its armature irrespective of tlie passage of said alternating currents.

In witness whereof, I hereunto subscribe my7name this 17th day of August, A. D. 191

SAMUEL HARRISON EVERETT. 

